Light emitting device package and application thereof

ABSTRACT

A light emitting device including a printed circuit board having a front surface and a rear surface, at least one light emitting source disposed on the front surface to emit light in a direction away from the printed circuit board, and a molding layer surrounding the light emitting source, in which the light emitting source includes a light emitting structure, a substrate disposed on the light emitting structure, and a plurality of bump electrodes disposed between the light emitting structure and the printed circuit board, the molding layer covers an upper surface of the substrate and a fine concavo-convex part is formed on a surface of the molding layer exposed to the outside, and the molding layer has a first thickness to transmit at least a fraction of light emitted from the light emitting source, and includes a filler to change a direction of emitted light.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.17/881,512, filed on Aug. 4, 2022, which is a Continuation of U.S.patent application Ser. No. 16/819,786, filed on Mar. 16, 2020, nowissued as U.S. Pat. No. 11,437,551, which claims the benefit of U.S.Provisional Application No. 62/820,482, filed on Mar. 19, 2019, each ofwhich is hereby incorporated by reference for all purposes as if fullyset forth herein.

BACKGROUND Field

Exemplary embodiments of the invention relate generally to a lightemitting device package and, more specifically, to an applicationthereof.

Discussion of the Background

Recently, various devices using a light emitting diode (LED) have beendeveloped. Examples of devices using a light emitting diode as a lightsource include general lighting and display devices. Structures of red“R” light emitting diode (LED), green “G” LED, and blue “B” LED aregrown individually, and are formed on a final substrate to obtaindevices using the light emitting diode

For applying the above-described light emitting diode to variousdevices, the structures may need to be simple to facilitate manufacture.

SUMMARY

Light emitting device packages constructed according to exemplaryembodiments of the invention have a simple structure that facilitatemanufacture.

Additional features of the inventive concepts will be set forth in thedescription which follows, and in part will be apparent from thedescription, or may be learned by practice of the inventive concepts.

A light emitting device package according to an exemplary embodimentincludes a printed circuit board having a front surface and a rearsurface, at least one light emitting device disposed on the frontsurface and emitting a light in a direction toward the front surface,and a molding layer disposed on the printed circuit board andsurrounding the light emitting device, in which the light emittingdevice includes a light emitting structure disposed on the printedcircuit board, a substrate disposed on the light emitting structure, anda plurality of bump electrodes disposed between the light emittingstructure and the printed circuit board, and the molding layer covers anupper surface of the substrate and includes a fine concavo-convex partformed on a surface of the molding layer exposed to the outside.

The fine concavo-convex part may be formed by at least one of plasmatreatment, micro sand blaster treatment, pattern transfer, drypolishing, and wet etching.

The molding layer may include fillers exposed through the finconcavo-convex part.

A top surface of the molding layer may have a substantially uniformheight throughout.

The molding layer may partially reflect, scatter, or absorb an externallight.

The molding layer may be at least partially filled between the lightemitting structure and the printed circuit board.

The molding layer may have an external light reflectance, an externallight scattering rate, or an external light absorbance of about 50% ormore.

The molding layer may have a black color.

The printed circuit board may include upper electrodes disposed on thefront surface, lower electrodes disposed on the rear surface, and viaelectrodes connecting the upper electrodes and the lower electrodes, andthe bump electrodes may be connected to corresponding upper electrodes.

A distance between two adjacent lower electrodes may be greater than adistance between two adjacent upper electrodes.

The light emitting device may be provided in plural. For example, thelight emitting devices may be provided in four, and the light emittingstructure of each light emitting device may include a plurality ofepitaxial stacks sequentially stacked on the substrate to emit lighthaving different wavelength bands from each other and having lightemitting regions overlapping one another.

The plurality of epitaxial stacks may include a first epitaxial stackemitting a first light, a second epitaxial stack provided on the firstepitaxial stack and emitting a second light having a wavelength banddifferent from a wavelength band of the first light, and a thirdepitaxial stack provided on the second epitaxial stack and emitting athird light of a wavelength band different from the wavelength bands ofthe first and second lights.

Each of the first to third epitaxial stacks may include a firstsemiconductor layer, a second semiconductor layer, and an active layerprovided between the first and second semiconductor layers.

The bump electrodes may include a first bump electrode connected to thefirst semiconductor layer of the first epitaxial stack, a second bumpelectrode connected to the first semiconductor layer of the secondepitaxial stack, a third bump electrode connected to the firstsemiconductor layer of the third epitaxial stack, and a fourth bumpelectrode connected to the second semiconductor layers of the first tothird epitaxial stacks.

The light emitting devices may include first to fourth light emittingdevices, the lower electrodes may include first to sixth scan pads andfirst and second data pads, the first light emitting device may beconnected to the first to third scan pads and the first data pad, thesecond light emitting device may be connected to the first to third scanpads and the second data pad, the third light emitting device may beconnected to the fourth to sixth scan pads and the first data pad, andthe fourth light emitting device may be connected to the fourth to sixthscan pads and the second data pad.

The bump electrodes in each light emitting device may include the firstto fourth bump electrodes, first to third scan signals may be applied tothe first to third bump electrodes, and a data signal may be applied tothe fourth bump electrode.

The molding layer may include an organic polymer material.

The light emitting device package may be employed in a display device ora vehicle lighting device. In this case, the light emitting devicepackage may include a base substrate and at least one light emittingdevice package provided on the base substrate.

A method of manufacturing a light emitting device package according toanother exemplary embodiment includes forming light emitting devices,mounting the light emitting devices on a printed circuit board, forminga molding layer on the printed circuit board using a vacuum laminatemethod to cover the light emitting devices, treating the surface of themolding layer exposed to the outside to form a fine concavo-convex parton the surface of the molding layer, and cutting the printed circuitboard and the molding layer to form the light emitting device package,in which the molding layer covers a top surface of the substrate andincludes a material which reflects, scatters, or absorbs some externallight.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate exemplary embodiments of theinvention, and together with the description serve to explain theinventive concepts.

The above and other objects and features will become apparent from thefollowing description with reference to the following figures, whereinlike reference numerals refer to like parts throughout the variousfigures unless otherwise specified, and wherein:

FIG. 1 is a cross-sectional view illustrating a light emitting deviceaccording to an exemplary embodiment.

FIG. 2A is a plan view illustrating a light emitting device according toan exemplary embodiment, and FIG. 2B is a cross-sectional view takenalong line A-A′ of FIG. 2A;

FIGS. 3A, 3B, 4A, 4B, 5A, 5B, 6A, 6B, 7A, and 7B sequentially illustratea method of manufacturing a light emitting device according to anexemplary embodiment. In particular, FIGS. 3A, 4A, 5A, 6A, and 7A areplan views, and FIGS. 3B. 4B, 5B, 6B, and 7B are cross-sectional viewstaken along line A-A′ of FIGS. 3A, 4A, 5A, 6A, and 7A.

FIGS. 8A, 8B, 8C, 8D, and 8E sequentially illustrate a method ofmanufacturing a light emitting device package according to an exemplaryembodiment.

FIGS. 9A and 9B are scanning electron microscope (SEM) photographsillustrating a molding layer with a plasma treatment and a mold layerwithout the plasma treatment, respectively.

FIGS. 10A, 10B, 10C, 10D, 10E, and 10E are cross-sectional viewssequentially illustrating a process of forming a fine concavo-convexpart on a surface of a molding layer using an imprint mold according toan exemplary embodiment.

FIG. 11A is a plan view illustrating a light emitting device packageaccording to an exemplary embodiment. In particularly, FIG. 11A is a topview illustrating four light emitting devices mounted in a matrix on oneprinted circuit board, and FIG. 11B is a rear view of the light emittingdevice package illustrated in FIG. 11A.

FIG. 12 is a circuit diagram of a light emitting device packageillustrated in FIGS. 11A and 11B.

FIG. 13 is a schematic cross-sectional view illustrating a light moduleby mounting a plurality of light emitting device packages on a basesubstrate for application to a display device or a vehicle lightingdevice.

FIG. 14 is a plan view exemplarily illustrating a light emitting devicepackage according to an exemplary embodiment applied to a displaydevice.

FIG. 15 is an enlarged plan view of portion P1 of FIG. 14 .

DETAILED DESCRIPTION

In the following description, for the purposes of explanation, numerousspecific details are set forth in order to provide a thoroughunderstanding of various exemplary embodiments or implementations of theinvention. As used herein “embodiments” and “implementations” areinterchangeable words that are non-limiting examples of devices ormethods employing one or more of the inventive concepts disclosedherein. It is apparent, however, that various exemplary embodiments maybe practiced without these specific details or with one or moreequivalent arrangements. In other instances, well-known structures anddevices are shown in block diagram form in order to avoid unnecessarilyobscuring various exemplary embodiments. Further, various exemplaryembodiments may be different, but do not have to be exclusive. Forexample, specific shapes, configurations, and characteristics of anexemplary embodiment may be used or implemented in another exemplaryembodiment without departing from the inventive concepts.

Unless otherwise specified, the illustrated exemplary embodiments are tobe understood as providing exemplary features of varying detail of someways in which the inventive concepts may be implemented in practice.Therefore, unless otherwise specified, the features, components,modules, layers, films, panels, regions, and/or aspects, etc.(hereinafter individually or collectively referred to as “elements”), ofthe various embodiments may be otherwise combined, separated,interchanged, and/or rearranged without departing from the inventiveconcepts.

The use of cross-hatching and/or shading in the accompanying drawings isgenerally provided to clarify boundaries between adjacent elements. Assuch, neither the presence nor the absence of cross-hatching or shadingconveys or indicates any preference or requirement for particularmaterials, material properties, dimensions, proportions, commonalitiesbetween illustrated elements, and/or any other characteristic,attribute, property, etc., of the elements, unless specified. Further,in the accompanying drawings, the size and relative sizes of elementsmay be exaggerated for clarity and/or descriptive purposes. When anexemplary embodiment may be implemented differently, a specific processorder may be performed differently from the described order. Forexample, two consecutively described processes may be performedsubstantially at the same time or performed in an order opposite to thedescribed order. Also, like reference numerals denote like elements.

When an element, such as a layer, is referred to as being “on,”“connected to,” or “coupled to” another element or layer, it may bedirectly on, connected to, or coupled to the other element or layer orintervening elements or layers may be present. When, however, an elementor layer is referred to as being “directly on,” “directly connected to,”or “directly coupled to” another element or layer, there are nointervening elements or layers present. To this end, the term“connected” may refer to physical, electrical, and/or fluid connection,with or without intervening elements. Further, the D1-axis, the D2-axis,and the D3-axis are not limited to three axes of a rectangularcoordinate system, such as the x, y, and z-axes, and may be interpretedin a broader sense. For example, the D1-axis, the D2-axis, and theD3-axis may be perpendicular to one another, or may represent differentdirections that are not perpendicular to one another. For the purposesof this disclosure, “at least one of X, Y, and Z” and “at least oneselected from the group consisting of X, Y, and Z” may be construed as Xonly, Y only, Z only, or any combination of two or more of X, Y, and Z,such as, for instance, XYZ, XYY, YZ, and ZZ. As used herein, the term“and/or” includes any and all combinations of one or more of theassociated listed items.

Although the terms “first,” “second,” etc. may be used herein todescribe various types of elements, these elements should not be limitedby these terms. These terms are used to distinguish one element fromanother element. Thus, a first element discussed below could be termed asecond element without departing from the teachings of the disclosure.

Spatially relative terms, such as “beneath,” “below,” “under,” “lower,”“above,” “upper,” “over,” “higher,” “side” (e.g., as in “sidewall”), andthe like, may be used herein for descriptive purposes, and, thereby, todescribe one elements relationship to another element(s) as illustratedin the drawings. Spatially relative terms are intended to encompassdifferent orientations of an apparatus in use, operation, and/ormanufacture in addition to the orientation depicted in the drawings. Forexample, if the apparatus in the drawings is turned over, elementsdescribed as “below” or “beneath” other elements or features would thenbe oriented “above” the other elements or features. Thus, the exemplaryterm “below” can encompass both an orientation of above and below.Furthermore, the apparatus may be otherwise oriented (e.g., rotated 90degrees or at other orientations), and, as such, the spatially relativedescriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particularembodiments and is not intended to be limiting. As used herein, thesingular forms, “a,” “an,” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise. Moreover,the terms “comprises,” “comprising,” “includes,” and/or “including,”when used in this specification, specify the presence of statedfeatures, integers, steps, operations, elements, components, and/orgroups thereof, but do not preclude the presence or addition of one ormore other features, integers, steps, operations, elements, components,and/or groups thereof. It is also noted that, as used herein, the terms“substantially,” “about,” and other similar terms, are used as terms ofapproximation and not as terms of degree, and, as such, are utilized toaccount for inherent deviations in measured, calculated, and/or providedvalues that would be recognized by one of ordinary skill in the art.

Various exemplary embodiments are described herein with reference tosectional and/or exploded illustrations that are schematic illustrationsof idealized exemplary embodiments and/or intermediate structures. Assuch, variations from the shapes of the illustrations as a result, forexample, of manufacturing techniques and/or tolerances, are to beexpected. Thus, exemplary embodiments disclosed herein should notnecessarily be construed as limited to the particular illustrated shapesof regions, but are to include deviations in shapes that result from,for instance, manufacturing. In this manner, regions illustrated in thedrawings may be schematic in nature and the shapes of these regions maynot reflect actual shapes of regions of a device and, as such, are notnecessarily intended to be limiting.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure is a part. Terms,such as those defined in commonly used dictionaries, should beinterpreted as having a meaning that is consistent with their meaning inthe context of the relevant art and should not be interpreted in anidealized or overly formal sense, unless expressly so defined herein.

FIG. 1 is a cross-sectional view illustrating a light emitting deviceaccording to an exemplary embodiment.

Referring to FIG. 1 , a light emitting device according to an exemplaryembodiment includes a light emitting structure including a plurality ofepitaxial stacks sequentially stacked. The light emitting structure isprovided on a substrate 11.

The substrate 11 may have a plate shape with a front surface and a rearsurface.

The light emitting structure may include at least two or more epitaxialstacks, each of which may emit light having a different wavelength band.In particular, the epitaxial stack is provided in plural numbers, andeach of the epitaxial stack may emit light having the same or differentenergy bands. In the illustrated exemplary embodiment, the lightemitting structure is illustrated as including three layers in whichepitaxial stacks are sequentially stacked on the front surface of thesubstrate 11. A third epitaxial stack 40, a second epitaxial stack 30,and a first epitaxial stack 20 are sequentially stacked on the frontsurface of the substrate 11.

The substrate 11 may be formed of a light transmissive insulatingmaterial.

The substrate 11 may be one of growth substrates capable of growing theepitaxial stack, e.g., the third epitaxial stack 40, on the frontsurface of the substrate 11. In an exemplary embodiment, the substrate11 may be sapphire (Al₂O₃), silicon carbide (SiC), gallium nitride(GaN), indium gallium nitride (InGaN), aluminum gallium nitride (AlGaN),aluminum nitride (AlN), gallium oxide (Ga₂O₃), or silicon (Si).

Each epitaxial stack emits light toward the rear surface of thesubstrate 11 (a lower direction in FIG. 1 ). In this case, light emittedfrom one epitaxial stack travels toward the rear surface of thesubstrate 11 while passing through another epitaxial stack located alongan optical path.

In the illustrated exemplar embodiment, the first epitaxial stack 20 mayemit a first light, the second epitaxial stack 30 may emit the secondlight, and the third epitaxial stack may emit a third light. The firstto third lights may be the same light or may be different light. In anexemplary embodiment, the first to third lights may be colored lights ina visible light wavelength band.

In an exemplary embodiment, the first to third lights may be lighthaving different wavelength bands having sequentially short wavelengths.More particularly, the first to third lights may have the same ordifferent wavelength bands. In addition, the first light to the thirdlight may have sequentially short wavelengths, which have sequentiallyhigh energy. In the illustrated exemplary embodiment, the first lightmay be a red light, the second light may be a green light, and the thirdlight may be a blue light. However, the first to third lights may belight having different wavelength bands sequentially having longwavelengths, or may be light having different wavelength bands arrangedirregularly regardless of the length of the wavelength. In one exemplaryembodiment, the first light may be a red light, the second light may bea blue light, and the third light may be a green light.

In the light emitting structure having the structure described aboveaccording to an exemplary embodiment, each epitaxial stack isindependently connected to each signal line for applying a lightemission signal, and thus, each epitaxial stack may be independentlydriven. In this manner, various colors may be implemented depending onwhether light is emitted from each epitaxial stack. In addition, theepitaxial stacks emitting light of different wavelengths are formed tovertically overlap each other, and thus, it is possible to form a smallarea.

In particular, in the light emitting stack structure according to anexemplary embodiment, the third epitaxial stack 40 may be provided onthe substrate 11, the second epitaxial stack 30 may be provided on thethird epitaxial stack 40 with a second adhesive layer 63 interposedtherebetween, and the first epitaxial stack 20 may be provided on thesecond epitaxial stack 30 with a first adhesive layer 61 interposedtherebetween.

The first and second adhesive layers 61 and 63 may be made of anon-conductive material, and include a material having lighttransmittance. For example, an optically clear adhesive may be used forthe first and second adhesive layers 61 and 63. However, the inventiveconcepts are not limited thereto, and in some exemplary embodiments, thefirst and second adhesive layers 61 and 63 may be optically transparentto a specific wavelength. For example, the first and second adhesivelayers 61 and 63 may be color filters showing a predetermined color bytransmitting only a specific wavelength. The color of the color filtersmay be selected from various colors, for example, may be red, blue, orgreen, or may be colors other than red, blue, or green.

The third epitaxial stack 40 includes an n-type semiconductor layer 41,an active layer 43, and a p-type semiconductor layer 45 sequentiallydisposed from bottom to top. The n-type semiconductor layer 41, theactive layer 43, and the p-type semiconductor layer 45 of the thirdepitaxial stack 40 may include a semiconductor material that may emitblue light. A third p-type contact electrode 45 p is provided on thep-type semiconductor layer 45 of the third epitaxial stack 40.

The second epitaxial stack 30 includes a p-type semiconductor layer 35,an active layer 33, an n-type semiconductor layer 31 sequentiallydisposed from bottom to top. The p-type semiconductor layer 35, theactive layer 33, and the n-type semiconductor layer 31 of the secondepitaxial stack 30 may include a semiconductor material that may emitgreen light. A second p-type contact electrode 35 p is provided underthe p-type semiconductor layer 35 of the second epitaxial stack 30.

The first epitaxial stack 20 includes a p-type semiconductor layer 25,an active layer 23, and an n-type semiconductor layer 21 sequentiallydisposed from bottom to top. The p-type semiconductor layer 25, theactive layer 23, and the n-type semiconductor layer 21 of the firstepitaxial stack 20 may include a semiconductor material that may emitred light. A first p-type contact electrode 25 p may be provided underthe p-type semiconductor layer 25 of the first epitaxial stack 20.

A first n-type contact electrode 21 n may be provided on the n-typesemiconductor layer 21 of the first epitaxial stack 20. The first n-typecontact electrode 21 n may be made of a single-layered metal or amulti-layered metal. For example, the first n-type contact electrode 21n may be formed with various materials including metal, such as Al, Ti,Cr, Ni, Au, Ag, Sn, W, Cu, or alloys thereof.

In the illustrated exemplary embodiment, the first to third p-typecontact electrodes 25 p, 35 p, and 45 p may be made of a transparentconductive material to transmit light.

In the illustrated exemplary embodiment, a common line may be connectedto the n-type semiconductor layers 21, 31, and 41 of the first to thirdepitaxial stacks 20, 30, and 40. The common line is a wire to which acommon voltage is applied. In addition, light emitting signal lines maybe connected to the p-type semiconductor layers 25, 35, and 45 of thefirst to third epitaxial stacks 20, 30, and 40 through the p-typecontact electrodes 25 p, 35 p, and 45 p, respectively. In particular, acommon voltage Sc is applied to the first n-type contact electrode 21 nand the second and third n-type semiconductor layers 31 and 41 throughthe common line, and light emission signals are applied to the p-typecontact electrodes 25 p, 35 p, and 45 p of the first to third epitaxialstacks 20, 30, and 40 through the light emission signal lines,respectively, to control light emission of the first to third epitaxialstacks 20, 30, and 40. In this case, the light emission signals includefirst to third light emission signals S_(R), S_(G), and S_(B)corresponding to each of the first to third epitaxial stacks 20, 30, and40. In an exemplary embodiment, the first emission signal S_(R) may be asignal corresponding to light emission of the red light, the secondemission signal S_(G) may be a signal corresponding to light emission ofthe green light, and the third emission signal S_(B) may be a signalcorresponding to light emission of the blue light.

According to the above-described exemplary embodiment, the first tothird epitaxial stacks 20, 30, and 40 are driven depending on the lightemission signals applied to the epitaxial stacks. More particularly, thefirst epitaxial stack 20 is driven depending on the first emissionsignal S_(R), the second epitaxial stack 30 is driven depending on thesecond emission signal S_(G), and the third epitaxial stack 40 is drivendepending on the third light emission signal S_(B). The first, second,and third emission signals S_(R), S_(G), and S_(B) are independentlyapplied to the first to third epitaxial stacks 20, 30, and 40, and thus,each of the first to third epitaxial stacks 20, 40 may be drivenindependently. In this manner, the light emitting stack structure mayprovide various colors and various amounts of light by the combinationof the first to third lights emitted downwardly from the first to thirdepitaxial stacks 20, 30, and 40.

In the above-described exemplary embodiment, although the common voltageis described as being provided to the n-type semiconductor layers 21,31, and 41 of the first to third epitaxial stacks 20, 30, and 40, andthe light emission signals are described as being applied to the p-typesemiconductor layers 25, 35, and 45 of the first to third epitaxialstacks 20, 30, and 40, respectively, the inventive concepts are notlimited thereto. For example, in some exemplary embodiments, the commonvoltage may be provided to the p-type semiconductor layers 25, 35, and45 of the first to third epitaxial stacks 20, 30, and 40, and the lightemission signals may be applied to the n-type semiconductor layers 21,31, and 41 of the first to third epitaxial stacks 20, and 40.

When the light emitting stack structure having the above structureaccording to an exemplary embodiment implements colors, different lightsmay not be implemented on different planes spaced apart from each other,but some of the different lights may be provided in an overlapping areato provide miniaturizing and integration of the light emitting device.According to an exemplary embodiment, when light emitting devicesimplementing different lights are stacked and partially overlapped oneover another in one area, full color may be implemented in asignificantly smaller area than a conventional light emitting device. Assuch, it is possible to manufacture a high resolution device even in asmall area. In addition, in the light emitting stack structure havingthe above structure, when the epitaxial stacks emitting light having thesame wavelength band are stacked, rather than epitaxial stacks emittinglight having the different wavelength bands, the intensity of lightemitted from the light emitting device may be controlled in variousways.

In the light emitting stack structure according to an exemplaryembodiment, after multiple epitaxial stacks are sequentially stacked onone substrate, a contact part may be formed on the multiple epitaxialstacks through a minimal process, and a wire is connected thereto. Inaddition, according to an exemplary embodiment, one light emitting stackstructure may be mounted, rather than a plurality of light emittingdevices as used in a conventional manufacturing method a display device,in which light emitting devices of individual colors are separatelymanufactured and mounted. As such, the manufacturing method according toan exemplary embodiment becomes remarkably simple.

The light emitting device according to an exemplary embodiment may beimplemented in various forms, one of which will be described withreference to FIGS. 2A and 2B.

FIG. 2A is a plan view illustrating a light emitting device according toan exemplary embodiment, and FIG. 2B is a cross-sectional view takenalong line A-A′ of FIG. 2A.

Referring to FIGS. 2A and 2B, a light emitting device according to anexemplary embodiment includes the substrate 11, a light emittingstructure provided on the substrate and including a plurality ofepitaxial stacks, and bump electrodes 20 bp, 30 bp, 40 bp, 50 bpprovided on the light emitting structure. The light emitting structureincludes the third epitaxial stack 40, the second epitaxial stack 30,and the first epitaxial stack 20 stacked on the substrate 11.

Each of the first to third epitaxial stacks 20, 30, and 40 includes thep-type semiconductor layer, the n-type semiconductor layer, and theactive layer provided between the p-type semiconductor layer and then-type semiconductor layer. In the drawing, the n-type semiconductorlayer, the p-type semiconductor layer, and the active layer of eachepitaxial stack are exemplarily illustrated as one epitaxial stack.

A third p-type contact electrode 45 p, the second adhesive layer 63, anda second p-type contact electrode 35 p are sequentially provided on thethird epitaxial stack 40. The second p-type contact electrode 35 p maybe in direct contact with the second epitaxial stack 30.

The first adhesive layer 61 and a first p-type contact electrode 25 pare sequentially provided on the second epitaxial stack 30. The firstp-type contact electrode 25 p may be in direct contact with the firstepitaxial stack 20.

The first n-type contact electrode 21 n is provided on the firstepitaxial stack 20. The first n-type semiconductor layer 21 may have astructure, in which a portion of an upper surface thereof is recessed,and the first n-type contact electrode 21 n may be provided in therecessed portion.

A single-layered or multi-layered insulating layer is provided on thesubstrate 11 on which the first to third epitaxial stacks 20, 30, and 40are stacked. In an exemplary embodiment, a first insulating layer 81 anda second insulating layer 83 may be provided on a portion of sidesurfaces and upper surfaces of the first and third epitaxial stacks 20,30 and 40 to cover a stack structure of the first to third epitaxialstacks 20, 30 and 40. The first and/or second insulating layers 81 and83 may be made of various organic/inorganic insulating materials, andthe materials and shapes thereof are not limited. For example, the firstand/or second insulating layers 81 and 83 may be provided as a siliconoxide layer, a silicon nitride layer, an aluminum oxide layer (Al₂O₃) ordistributed Bragg reflectors (DBRs). In addition, the first and/orsecond insulating layers 81 and 83 may be black organic polymer films.

A contact part is provided in the pixel to connect a wiring part to thefirst to third epitaxial stacks 20, 30, and 40. The contact partincludes a first contact part 20C for providing a light emission signalto the first epitaxial stack 20, a second contact part 30C for providinga light emission signal to the second epitaxial stack 30, a thirdcontact part 40C for providing a light emission signal to the thirdepitaxial stack 40, and a fourth contact part 50C for applying thecommon voltage to the first to third epitaxial stacks 20, 30, and 40. Inan exemplary embodiment, the first to fourth contact parts 20C, 30C,40C, and 50C may be provided at various positions in plan view.

The first to fourth contact parts 20C, 30C, 40C, and 50C may includefirst to fourth pads 20 pd, 30 pd, 40 pd, and 50 pd and the first tofourth bump electrodes 20 bp, 30 bp, 40 bp, and 50 bp, respectively.

Each of the first to fourth pads 20 pd, 30 pd, 40 pd, and 50 pd isspaced apart from one another to be insulated from each other.

Each of the first to fourth bump electrodes 20 bp, 30 bp, 40 bp, and 50bp may be insulated from and spaced apart from one another, and may beprovided in an area overlapping the first to third epitaxial stacks 20,30, and 40, such as a light emission area thereof. Each of the first tofourth bump electrodes 20 bp, 30 bp, 40 bp, and 50 bp may be formed overan edge of each of the first to third epitaxial stacks 20, 30, and 40,thereby covering the side surfaces of the active layers of the first tothird epitaxial stacks 20, 30, and 40.

The first contact part 20C includes the first pad 20 pd and the firstbump electrode electrically connected to each other. The first pad 20 pdis provided on the first p-type contact electrode 25 p of the firstepitaxial stack 20, and is connected to the first p-type contactelectrode 25 p through a first contact hole 20CH provided in the firstinsulating layer 81. The first bump electrode 20 bp at least partiallyoverlaps the first pad 20 pd. The first bump electrode 20 bp isconnected to the first pad 20 pd through a first through hole 20 ct in aregion overlapping the first pad 20 pd with the second insulating layer83 interposed therebetween.

The second contact part 30C includes the second pad 30 pd and the secondbump electrode 30 bp electrically connected to each other. The secondpad 30 pd is provided on the second p-type contact electrode 35 p, andis connected to the second p-type contact electrode 35 p through asecond contact hole 30CH formed in the first insulating layer 81. Thesecond bump electrode 30 bp at least partially overlaps the second pad30 pd. The second bump electrode 30 bp is connected to the second pad 30pd through a second through hole 30 ct in a region overlapping thesecond pad 30 pd with the second insulating layer 83 interposedtherebetween.

The third contact part 40C includes the third pad 40 pd and the thirdbump electrode 40 bp electrically connected to each other. The third pad40 pd is provided on the third p-type contact electrode 45 p, and isconnected to the third p-type contact electrode 45 p through a thirdcontact hole 40CH formed in the first insulating layer 81. The thirdbump electrode 40 bp at least partially overlaps the third pad 40 pd.The third bump electrode 40 bp is connected to the third pad 40 pdthrough a third through hole 40 ct in a region overlapping the third pad40 pd with the second insulating layer 83 therebetween.

The fourth contact part 50C includes the fourth pad 50 pd and the fourthbump electrode 50 bp electrically connected to each other. The fourthpad 50 pd is connected to the first to third epitaxial stacks 20, 30,and 40 through first to third sub contact holes 50CHa, 50CHb, and 50CHc,which are respectively provided on the first n-type contact electrode 21n, the second and third n-type semiconductor layers of the first tothird epitaxial stacks 20, 30, and 40, respectively. An upper surface ofthe third epitaxial stack 40 may be partially removed to expose thethird n-type semiconductor layer, such that the fourth pad 50 pd isconnected to the third n-type semiconductor layer of the third epitaxialstack 40.

In particular, the fourth pad 50 pd is connected to the first epitaxialstack 20 through a first sub contact hole 50CHa provided on the firstn-type contact electrode of the first epitaxial stack 20, is connectedto the second epitaxial stack 30 through a second sub contact hole 50CHbprovided on the second n-type semiconductor layer of the secondepitaxial stack 30, and is connected to third epitaxial stack 40 througha third sub contact hole 50CHc provided on the third n-typesemiconductor layer of the third epitaxial stack 40. The fourth bumpelectrode at least partially overlaps the fourth pad 50 pd. The fourthbump electrode 50 bp is connected to the fourth pad 50 pd through afourth through hole 50 ct in a region overlapping the fourth pad 50 pdwith the second insulating layer 83 interposed therebetween.

In an exemplary embodiment, the wiring part provided to correspond tothe first to fourth contact parts 20C, 30C, 40C, and 50C, andelectrically connected to the first to fourth bump electrodes 20 bp, 30bp, 40 bp, and 50 bp, respectively (see FIG. 5 ), and/or a drivingdevice such as a thin film transistor connected to the wiring part maybe further provided in the substrate 11. For example, the first to thirdepitaxial stacks 20, 30, 40 may be connected to first to third lightemission signal lines providing the light emission signals to the firstto third epitaxial stacks 20, 30, and 40 through the first to third bumpelectrodes 20 bp, 30 bp, and 40 bp, respectively, and a common lineproviding the common voltage to each of the first to third epitaxialstacks 20, 30, and 40 through the fourth bump electrode 50 bp. In theillustrated exemplary embodiment, the first to third light emittingsignal lines may correspond to first to third scan lines, and the commonline may correspond to a data line, respectively.

FIGS. 3A to 7B sequentially illustrate a method of manufacturing a lightemitting device according to an exemplary embodiment. In particular,FIGS. 3A, 4A, 5A, 6A, and 7A are plan views, and FIGS. 3B. 4B, 5B, 6B,and 7B are cross-sectional views taken along line A-A′ of FIGS. 3A, 4A,5A, 6A, and 7A, respectively.

Referring to 3A and 3B, a light emitting structure is formed on thesubstrate 11. In the light emitting structure, the third epitaxial stack40, the third p-type contact electrode 45 p, the second adhesive layer63, the second p-type contact electrode 35 p, the second epitaxial stack30, the adhesive layer 61, the first p-type contact electrode 25 p, thefirst epitaxial stack 20, and the first n-type contact electrode 21 nmay be sequentially formed by various methods, such as chemical vapordeposition, metal organic chemical vapor deposition, and molecular beamdeposition.

The light emitting structure may be patterned in various shapes inconsideration of an overall wire connection structure. For example, thecontact holes, through holes, and pads may be formed in a polygonalshape when viewed in plan view.

According to an exemplary embodiment, the first to third epitaxialstacks 20, 30, and 40 and the first to third p-type contact electrodes25 p, 35 p, and 45 p may be partially removed through an etching processto expose upper surfaces thereof to which the first and fourth contactholes 20CH, 30CH, 40CH, and 50CH (see FIGS. 4A and 4B) are to be formed.

Referring to 4A and 4B, the first insulating layer 81 may be formedconformally on the vertically stacked light emitting structure. Thefirst insulating layer 81 may include an oxide, for example, siliconoxide and/or silicon nitride.

The first insulating layer 81 is patterned to remove a portion thereof,thereby forming the first to fourth contact holes 20CH, 30CH, 40CH, and50CH.

The first contact hole 20CH is disposed on the first p-type contactelectrode 25 p to partially expose the first p-type contact electrode 25p. The second contact hole 30CH is disposed on the second epitaxialstack 30 to partially expose the second p-type contact electrode 35 p.The third contact hole 40CH is disposed on the third p-type contactelectrode 45 p to partially expose the third p-type contact electrode 45p. The fourth contact hole 50CH includes the first to third sub contactholes 50CHa, 50CHb and 50CHc, and the first to third sub contact holes50CHa, 50CHb and 50CHc are disposed on the first n-type contactelectrode 21 n, the second n-type semiconductor layer of the secondepitaxial stack 30, and the third n-type semiconductor layer of thethird epitaxial stack 40, respectively, to partially expose the firstn-type contact electrode 21 n, the second n-type semiconductor layer ofthe second epitaxial stack and the third n-type semiconductor layer ofthe third epitaxial stack 40.

Referring to 5A and 5B, the first to fourth pads 20 pd, 30 pd, 40 pd,and 50 pd are formed on the first insulating layer 81 on which the firstto fourth contact holes 20CH, 30CH, and 50CH are formed. Variousconductors including metal may be used as a conductive film material forforming the first to fourth pads 20 pd, 30 pd, 40 pd, and 50 pd. Forexample, the first to fourth pads 20 pd, 30 pd, 40 pd, and 50 pd mayinclude at least one of Ni, Ag, Au, Pt, Ti, At, Al and Cr.

The first to fourth pads 20 pd, 30 pd, 40 pd, and 50 pd are formed topartially overlap portions where the first to fourth contact holes 20CH,30CH, 40CH, and 50CH are formed, respectively. The fourth pad 50 pd maybe formed to generally overlap a portion where the first to third subcontact holes 50CHa, 50CHb, and 50CHc are formed.

Referring to 6A and 6B, the second insulating layer 83 may be formedconformally on the first insulating layer 81. The second insulatinglayer 83 may include an oxide, for example, silicon oxide and/or siliconnitride.

The second insulating layer 83 is patterned to remove a portion thereof,and thus, the first to fourth through holes 20 ct, 30 ct, 40 ct, and 50ct are formed.

The first to fourth through holes 20 ct, 30 ct, 40 ct, and 50 ct aredisposed on the first to fourth pads 20 pd, 30 pd, 40 pd, and 50 pd,respectively, to partially expose the first to fourth pads 20 pd, 30 pd,40 pd, and 50 pd.

Referring to 7A and 7B, the first to fourth bump electrodes 20 bp, 30bp, 40 bp, and are formed on the second insulating layer 83, on whichthe first to fourth through holes 30 ct, 40 ct, and 50 ct are formed.

The first to fourth bump electrodes 20 bp, 30 bp, 40 bp, and 50 bp areformed to overlap with portions where the first to fourth through holes20 ct, 30 ct, 40 ct, and 50 ct are formed, respectively. As such, thefirst to fourth bump electrodes 20 bp, 30 bp, 40 bp, and 50 bp areconnected to the first to fourth pads 20 pd, 30 pd, 40 pd, and 50 pdthrough the first to fourth through holes 20 ct, 30 ct, 40 ct, and 50ct, respectively.

Each of the first to fourth bump electrodes 20 bp, 30 bp, 40 bp, and 50bp may have a larger area than the corresponding first to fourth pads 20pd, 30 pd, 40 pd, and 50 pd. In addition, the first to fourth bumpelectrodes 20 bp, 30 bp, 40 bp, and 50 bp may at least partially overlapthe light emission region from which the first to third epitaxial stacks20, 30 and 40 emit light.

The first to fourth bump electrodes 20 bp, 30 bp, 40 bp, 50 bp may beformed by a plating method using various metals. The first to fourthbump electrodes 20 bp, 30 bp, 40 bp, and may further include a seedlayer for forming a metal layer in the plating process. As the seedlayer, various metals, for example, metal including Cu, Ni, Ti, and thelike may be used, which may be variously changed depending on the metalmaterial to be plated.

When the first to fourth bump electrodes 20 bp, 30 bp, 40 bp, and 50 bpare formed by the plating method, it is possible to form a flat uppersurface on each of the first to fourth bump electrodes 20 bp, 30 bp, 40bp, and 50 bp. The light emitting structure may have an upper step dueto etching to form a contact structure for connection with an externalwire, and thus, when connecting to another device and when a generalmetal layer is formed, it may be difficult to make an electricalconnection between another device and the light emitting structure dueto the step. However, when the first to fourth bump electrodes 20 bp, 30bp, 40 bp, and 50 bp formed by the plating method, it is possible toform electrodes having a flat top surface even on the light emittingstructure including the epitaxial layer having a severe step. Inaddition, while the plated first to fourth bump electrodes 20 bp, 30 bp,40 bp, and 50 bp may have a flat top surface, an additional polishingprocess may be performed on the upper surfaces of the first to fourthbump electrodes 20 bp, 30 bp, 40 bp, and 50 bp to increase the flatness.

The material of the first to fourth bump electrodes 20 bp, 30 bp, 40 bp,and 50 bp may be not particularly limited, as long as it can be used asa wiring material in a semiconductor device. For example, the first tofourth bump electrodes 20 bp, 30 bp, 40 bp, and 50 bp may be formed of,metal, such as CuAg, Sb, Ni, Zn, Mo, Co, and the like and/or metalalloys thereof. In an exemplary embodiment of the inventive concept, thefirst to fourth bump electrodes 20 bp, 40 bp, 50 bp may be made of onlySn, or may be made of Cu/Ni/Sn. When the first to fourth bump electrodes20 bp, 30 bp, 40 bp, and 50 bp are made of Cu/Ni/Sn, internal diffusionof impurities into the light emitting structure may be minimized, and inparticular, Cu used as a material of the bump electrodes may preventpenetration of Sn into the light emitting structure.

The first to fourth bump electrodes 20 bp, 30 bp, 40 bp, and 50 bp maybe formed using the plating method, and then an additional heattreatment process, that is, a reflow process, may be performed toincrease the strength of the first to fourth bump electrodes 20 bp, 30bp, 40 bp, and 50 bp.

In an exemplary embodiment, the light emitting device having thestructure as described above may be implemented as a package and mountedon another device, for example, a printed circuit board to function asone light emitting device package. Accordingly, various wires may beadditionally provided to have a structure that facilitates mountingprocess to other devices.

FIGS. 8A to 8E sequentially illustrate a method of manufacturing a lightemitting device package. In FIGS. 8A and 8E, the first to thirdepitaxial stacks are exemplarily illustrated as a light emittingstructure 10 and the first to fourth pads and the first to fourth bumpelectrodes are exemplarily illustrated as a pad “pd” and a bumpelectrode “bp”. In particular, in the drawings, the light emittingstructure 10 is exemplarily illustrated as being simply flat, but has astep and/or a slope on the upper surface thereof as described above.

In an exemplary embodiment, at least one light emitting device 110 maybe mounted on a printed circuit board 11 p having a wire or the like toform the light emitting device package. The light emitting devicepackage may include a plurality of light emitting devices 110.

Referring to FIG. 8A, the printed circuit board 11 p is prepared and theplurality of light emitting devices 110 are disposed on the printedcircuit board 11 p.

The printed circuit board 11 p may be formed with wires and electrodesfor electrical connection between various devices, and at least onelight emitting device 110 may be mounted on a surface of the printedcircuit board 11 p. The printed circuit board 11 p may be provided invarious forms depending on an arrangement of the wires. According to theillustrated exemplary embodiment, the electrodes are provided on a frontsurface, a rear surface, and a portion between the front surface and therear surface of the substrate 11. However, the arrangement of the wiresof the printed circuit board 11 p is not limited thereto. In anexemplary embodiment, the printed circuit board 11 p may or may not haveflexibility.

In an exemplary embodiment, the printed circuit board 11 p has the frontsurface and the rear surface. Upper electrodes 11 pa are provided on thefront surface of the printed circuit board 11 p, lower electrodes 11 pcare provided on the rear surface, and via electrodes 11 pb penetrate theprinted circuit board 11 p to connect the upper electrodes 11 pa and thelower electrodes 11 pc. The front surface of the printed circuit board11 p is a surface on which the light emitting devices 110 are mounted.In an exemplary embodiment of the inventive concept, the upperelectrodes 11 pa of the printed circuit board 11 p are formed atpositions corresponding to the bump electrodes bp of each light emittingdevice 110 to be attached later.

The surfaces of the wires and/or the electrodes on the printed circuitboard 11 p may be treated with electroless nickel immersion gold (ENIG).For example, in an exemplary embodiment, in particular, the surfaces ofthe upper electrodes 11 pa may be treated with ENIG. When the wiresand/or the electrodes on the printed circuit board 11 p are treated withENIG, the wires and/or the electrodes may partially melt at a hightemperature to facilitate connection to the bump electrodes bp of thelight emitting devices 110.

The light emitting devices 110 are attached on a carrier substrate 11 cto be disposed on the printed circuit board 11 p. The carrier substrate11 c is for transporting the light emitting devices 110. An adhesivelayer 13 is formed on one surface of the carrier substrate 11 c, and thelight emitting devices 110 are attached to the carrier substrate 11 c bythe adhesive layer 13. The adhesive layer 13 may be a silicon-basedpolymer having strong heat resistance and capable of detaching the lightemitting devices 110. The adhesive layer 13 may be manufactured in atape or sheet form, and may be provided on a rear surface of the carriersubstrate 11 c. The adhesive layer 13 has an adhesive strength to stablyattach the light emitting devices 110 to the carrier substrate 11 c,while allowing the light emitting devices 110 be easily detachedtherefrom when the light emitting devices 110 are attached to theprinted circuit board 11 p. In particular, the adhesive strength of theadhesive layer 13 to the light emitting devices 110 may be less than anadhesive strength between the light emitting devices 110 and the printedcircuit board 11 p.

The light emitting devices 110 may be attached on the rear surface ofthe carrier substrate 11 c in an inverted form, such that the substrate11 is positioned above the light emitting structure 10. Moreparticularly, the light emitting device 110 attached to the carriersubstrate 11 c has the inverted form, such that the rear surface of thesubstrate 11 is attached to the adhesive layer 13 on the carriersubstrate 11 c. The light emitting devices 110 are spaced apart fromeach other on the printed circuit board 11 p while being attached to thecarrier substrate 11 c.

Referring to FIG. 8B, the light emitting devices 110 are attached on theprinted circuit board 11 p, and the carrier substrate 11 c and theadhesive layer 13 are removed. The light emitting devices 110 attachedto the carrier substrate 11 c may be compressed downwardly, such thatthe bump electrodes bp may be in contact with the corresponding upperelectrodes 11 pa of the printed circuit board 11 p. The pressingoperation may be performed at a high temperature, and thus, the upperelectrodes 11 pa on the printed circuit board 11 p may be partially meltto be connected to the bump electrodes bp of the light emitting devices110. The carrier substrate 11 c may be then removed, and the adhesivelayer 13 on the carrier substrate 11 c may have a weaker adhesivestrength than the adhesive strength between the bump electrodes bp ofthe light emitting devices 110 and the upper electrodes 11 pa of theprinted circuit board 11 p to facilitate the separation of the carriersubstrate 11 c from the light emitting devices 110.

The above-described bump electrodes bp are attached to the upperelectrodes 11 pa of the printed circuit board 11 p, and thus, an overallstructure may include the printed circuit board 11 p, the bumpelectrodes bp, the pads pd, the light emitting structure 10, and thesubstrate 11 sequentially disposed one over another. Light from thelight emitting structure 10 travels from the light emitting structure 10in a direction toward the rear surface of the substrate 11 (a upwarddirection in the drawing), and thus, light may be mitted towards adirection to which the front surface of the printed circuit board 11 pfaces.

Referring to FIG. 8C, a molding layer 90 is formed on the printedcircuit board 11 p on which the light emitting devices 110 are mounted.The molding layer 90 has characteristics of at least partiallytransmitting the light, but partially reflects, scatters, and/or absorbsexternal light. The molding layer 90 at least partially covers the lightemitting device 110 and partially reflects, scatters, and/or absorbsexternal light in various directions to prevent the external light fromreflecting in a specific direction, in particular, a direction which isvisible to a user. In addition, the molding layer 90 at least partiallycovers the light emitting device 110 to prevent damage to the lightemitting device 110 from moisture and/or physical impact from theoutside, thereby increasing the reliability of the light emitting device110.

The molding layer 90 may allow some external light to be reflected,scattered, and/or absorbed in various directions. In particular, themolding layer 90 may have a black color, without being limited thereto.In some exemplary embodiments, the molding layer 90 may have a colorother than the black color, as long as some external light can bereflected, scattered, and/or absorbed in various directions to preventthe reflection of the external light toward the user.

For preventing reflection of the external light in the specificdirection, the molding layer 90 at least partially surrounds the lightemitting device 110. In particular, the molding layer 90 is formed tocover the rear surface of the substrate 11 in the light emitting device110. In an exemplary embodiment, the molding layer 90 is formed to coverthe rear surface of the substrate 11, and thus, light from the outsidemay be prevented from being reflected by the rear surface of thesubstrate 11 towards the user. For preventing reflection of the externallight in the specific direction, the molding layer 90 may reflect,scatter, or absorb about 50% or more of the external light in variousdirections. In an exemplary embodiment, the molding layer 90 mayreflect, scatter or absorb about 80% or more of external light.

The molding layer 90 may be formed to have a thickness capable of beingtransmissive, and thus, light emitted from the light emitting structure10 toward the rear direction (i.e., the upward direction) of thesubstrate 11 may be maximally emitted. For example, the molding layer 90may be formed to a thickness through which at least 50% of light fromthe light emitting structure is transmitted when provided on the rearsurface of the light emitting structure and may be provided to have athickness less than about 100 micrometers in height from the rearsurface of the light emitting structure. Alternatively, the moldinglayer 90 may be provided to have the height less than the thickness ofthe light emitting device from the rear surface of the light emittingstructure.

The molding layer 90 may be not only formed on the rear surface of thesubstrate 11, but also on the side surface of the light emitting device110, that is, may cover the side surface of the substrate 11 and sidesurface of the light emitting structure 10. The molding layer alsocovers the side surface of the light emitting device 110, and thus,light emitted through the side surface of the light emitting device 110may be at least partially absorbed by the molding layer 90. Accordingly,the molding layer 90 may prevent light emitted from one light emittingstructure 10 from being mixed with light emitted from adjacent lightemitting structure 10.

In an exemplary embodiment, the molding layer 90 may be made of anorganic polymer, which absorbs light among organic polymers. In anexemplary embodiment, the molding layer 90 may or may not furtherinclude an organic/inorganic filler therein in addition to the organicpolymer. For example, when the molding layer 90 includes a filler, thefiller may be an inorganic filler. Various inorganic fillers may beused, for example, silica, alumina, or the like.

In addition, the molding layer 90 is filled in at least a portionbetween the light emitting structure 10 and the printed circuit board 11p. More particularly, the molding layer 90 may fill an empty spacebetween the light emitting structure 10 provided with the bumpelectrodes bp and the printed circuit board 11 p. The space between thelight emitting structure 10 and the printed circuit board 11 p may befilled with the molding layer 90, and thus, the molding layer 90 mayeffectively dissipate heat generated from the light emitting structure10, thereby improving heat dissipation characteristics of the lightemitting devices 110.

In an exemplary embodiment, the molding layer 90 may be manufactured invarious ways, such as a lamination method, a coating method, a chemicalvapor deposition method, a printing method, a transfer molding method,or the like. The manufacturing of the molding layer 90 may include anadditional process to planarize the surface of the molding layer andvarious thinning processes may be used. For example, for planarizationof the surface of the molding layer 90, squeegeeing may performed to amaterial of the molding layer 90, or pressurized planarization may beperformed using a flat plate, after application before curing. Inaddition, polishing or lapping may be performed on the surface after themolding layer 90 material is cured.

In one exemplary embodiment, the molding layer 90 is formed by thetransfer molding method to obtain a flat upper surface of the moldinglayer 90. The transfer molding method may be performed through extrusionmolding, in which a unit of a package including a light emitting deviceis provided on a molding die, and then be press-molded with resinliquefied in a solid state into the mold.

A laminating method for planarizing the surface of the molding layer 90may be a vacuum laminate method performed in a vacuum. In this case, themolding layer 90 may be formed of an organic polymer sheet having a filmshape. The organic polymer sheet may be disposed on the printed circuitboard 11 p on which the light emitting devices 110 are mounted, and thenmay be heated and pressed under a vacuum condition to form the moldinglayer 90. The organic polymer sheet may partially show fluidity at hightemperature and high pressure, and may fill the area between the lightemitting devices 110 and the space between the light emitting devices110 and the printed circuit board 11 p due to the fluidity. The organicpolymer sheet is then cured.

In an exemplary embodiment, the molding layer 90 may be formed by avacuum lamination method to obtain a flat top surface of the moldinglayer 90. In general, an organic polymer material is applied and then iscured to form the molding layer. In this case, a difference in theheight of the top surface of the molding layer 90 may be caused betweena region where the light emitting devices 110 are mounted and a regionwhere the light emitting devices 110 are not mounted. The difference inthe upper surface height causes non-uniformity of light emitted from thelight emitting devices 110. However, according to an exemplaryembodiment, the upper surface of the molding layer 90 is flat toincrease the uniformity of light regardless of the positions of thelight emitting devices 110.

In addition, the molding layer 90 may be provided to stably hold thelight emitting devices 110, and thus, the rigidity of the light emittingdevice package may be increased. In particular, the molding layer 90 mayfill the space between the printed circuit board 11 p and the lightemitting devices 110 to increase the adhesion between the printedcircuit board 11 p and the light emitting devices 110. Accordingly, therigidity of the entire light emitting device package is furtherincreased.

Referring to FIG. 8D, the surface of the molding layer 90 is textured toform a fine concavo-convex part 91 on the surface of the molding layer90, which is exposed to the outside. The fine concavo-convex part 91generates diffuse reflection. As such, the reflection of external lightis further minimized in the user's field of vision due to the diffusereflection of the external light by the fine concavo-convex part 91.When the light emitting device package is used in a variety ofapplications, such as lighting or display device, the substrate 11 ofthe light emitting device is disposed at a position facing the user'sline of sight, and thus, it is necessary to prevent light reflected bythe substrate 11 as much as possible. Accordingly, the fineconcavo-convex part 91 is additionally formed in the molding layer 90 tohave light scattering property, light reflecting property, and lightabsorbing property, thereby reducing glare to the user that may becaused from the reflection of external light.

In an exemplary embodiment, the molding layer 90 may further include afiller, such as silica or alumina therein, and thus, filler particlesmay be exposed to the surface of the molding layer 90 after texturing.In this case, the filler particles may be randomly exposed on thesurface to further improve the scattering degree of external light.

The fine concavo-convex part 91 may be formed in various methods. In anexemplary embodiment, the surface of the molding layer 90 may be etchedusing plasma.

FIGS. 9A and 9B are SEM photographs showing a surface of a molding layerwith a plasma treatment, and a surface of a molding layer without theplasma treatment, respectively.

Referring to FIG. 9A, it may be seen that a plurality of fillers arerandomly exposed to the outer surface of the molding layer after theplasma treatment. The plurality of fillers may be exposed to the outersurface in various sizes and frequencies, thereby significantlyincreasing the external light scattering effect on the filler.

On the other hand, referring to FIG. 9B, it may be seen that the numberof fillers exposed on the surface is remarkably small when not treatedwith the plasma treatment, as compared to that of FIG. 9A. Accordingly,it may be seen that the fine concavo-convex part can be easily formed onthe surface of the molding layer 90 using the plasma treatment.

In this case, a change in the components of the molding layer 90 is notobserved by analyzing the components of the molding layer 90 before orafter the plasma treatment, and thus, it may be seen that the fineconcavo-convex part can be formed on the molding layer 90 withoutchanges in the components thereof.

In an exemplary embodiment, in addition to the plasma treatment, thefine concavo-convex part may be formed by roughening the surface using amicro sand blaster. In the case of using the micro sand blaster, fineparticles of several micrometers to several tens of micrometers may besprayed at a high pressure on the surface of the molding layer, and thesurface of the molding layer may be cleaned by ultrasonic cleaning orthe like, and dried to form the fine concavo-convex part on the surfaceof the molding layer. Alternatively, a method such as dry grinding orwet etching the surface of the molding layer 90 may be used alone or incombination with the above-described method.

According to an exemplary embodiment, fine concavo-convex patterns maybe transferred to the surface of the molding layer using an imprint moldhaving a fine concavo-convex pattern, and thus, the concavo-convex partmay be formed on the surface of the molding layer.

FIGS. 10A to 10E are cross-sectional views sequentially illustrating aprocess of forming a fine concavo-convex part on a surface of a moldinglayer using an imprint mold according to an exemplary embodiment.

Referring to FIG. 10A, first, a master mold MM is prepared. The mastermold MM is formed with a pattern 91 that may form the fineconcavo-convex part to be transferred to the surface of the moldinglayer, and is used to form an inverse pattern on an imprint mold IMP.

Referring to FIG. 10B, a material of the imprint mold IMP is applied onthe master mold MM. The imprint mold IMP is cured, and then the imprintmold IMP is separated from the master mold MM. As such, an inversepattern 91R of the fine concavo-convex part on the master mold MM isformed on a surface of the imprint mold IMP.

Referring to FIG. 10C, the imprint mold IMP having the inverse pattern91R is disposed on the molding layer 90 and then pressed from the top tothe bottom.

Referring to FIG. 10D, the inverse pattern 91R of the imprint mold IMPis transferred to the upper surface of the molding layer 90 by pressingthe imprint mold IMP, and the imprint mold IMP is separated from themolding layer 90 after the transfer.

Referring to FIG. 10E, the fine concavo-convex part 91 is formed on theupper surface of the molding layer 90 by removing the imprint mold IMP.

According to illustrated exemplary embodiment, a shape of the fineconcavo-convex part formed in the molding layer 90 is determineddepending on a shape of the fine concavo-convex pattern formed on themaster mold MM. Accordingly, the fine concavo-convex pattern of themaster mold MM may be formed to various shapes, as necessary.Accordingly, the shape, density, and the like of the fine concavo-convexpart of the molding layer MM may be controlled, and thus, the degree ofscattering of external light by the upper surface of the concavo-convexpart of the molding layer 90 may be easily adjusted.

Referring back to FIG. 8E, after the molding layer 90 having the fineconcavo-convex part is formed, the printed circuit board 11 p and thelight emitting device 110 are cut into an appropriate size as a lightemitting device package. The printed circuit board 11 p and the lightemitting device 110 may be cut, such that the light emitting devicepackage includes one light emitting device 110 therein, or may be cut tohave a large area, such that the light emitting device package includesa plurality of the light devices 110 therein. The number and area of thelight emitting device 110 may be cut differently set depending on adevice to which the light emitting device 110 are to be mounted.

In the light emitting device package, the number of light emittingdevice mounted on the printed circuit board forming one light emittingdevice package may be variously changed. FIG. 11A is a plan viewillustrating a light emitting device package according to an exemplaryembodiment. In particular, FIG. 11A is a top view illustrating fourlight emitting device mounted in a matrix on a printed circuit board,and FIG. 11B is a rear view of a light emitting device packageillustrated in FIG. 11A. FIG. 12 is a circuit diagram of a lightemitting device package illustrated in FIGS. 11A and 11B.

Referring to FIGS. 11A, 11B, and 12 , a light emitting device package110D includes the printed circuit board 11 p and four light emittingdevice 110 mounted in a 2×2 arrangement on the printed circuit board 11p. However, the number and arrangement of the light emitting devicepackages 110D is not limited thereto, and may be arranged in variousmatrix forms, for example, 1×1, 3×3, 4×4, and the like. As describedabove, each light emitting device 110 has a structure, in which first tothird epitaxial stacks are stacked in a vertical direction. Accordingly,each of the first to third epitaxial stacks corresponds to lightemitting diodes each generating light. For example, the first to thirdepitaxial stacks may correspond to the first light emitting diodeemitting the red light, the second light emitting diode emitting thegreen light, and the third diode emitting the blue light, respectively.

Referring to FIG. 12 , for driving four light emitting device, first tosixth scan lines SC1, SC2, SC3, SC4, SC5, and SC6, and first and seconddata lines DT1 and DT2 are connected to the four light emitting device.When the four light emitting device are referred to as first to fourthlight emitting device 110 p, 110 q, 110 r, and 110 s, the first lightemitting device 110 p is connected to the first to third scan lines SC1,SC2, and SC3 and the first data line D1, the second light emittingdevice 110 q is connected to the first to third scan lines SC1, SC2, andSC3 and the second data line DT2. The third light emitting device 110 ris connected to the fourth to sixth scan lines SC4, SC5, and SC6 and thefirst data line DT1, and the fourth light emitting device 110 s isconnected to the fourth to six scan lines SC4, SC5 and SC6 and thesecond data line DT2.

Three light emitting diodes included in each of the first to fourthlight emitting device 110 p, 110 q, 110 r, and 110 s may eachselectively emit light corresponding to a data signal input through thedata line when a scan signal is supplied through the scan line. When avoltage higher than a threshold voltage is applied, the diodes areconnected between the scan lines and the data lines to emit light with aluminance corresponding to a level of the applied voltage. Inparticular, a voltage of the scan signal applied to the scan line and/orthe data signal applied to the data line may be adjusted to controllight emission of each light emitting diode. For example, each lightemitting diode emits light at a luminance corresponding to the inputdata signal during each frame period. The light emitting diodes suppliedwith the data signal corresponding to black luminance do not emit lightduring the corresponding frame period to display black.

In an exemplary embodiment, the six scan lines and two data lines may beprovided, thereby individually driving the first to fourth lightemitting device 110 p, 110 q, 110 r, and 110 s.

To this end, the light emitting devices are mounted at correspondingpositions on the printed circuit board 11 p. Referring back to FIGS. 11Aand 11B, upper electrodes 11 pa are provided on the front surface of theprinted circuit board 11 p at the positions corresponding to the lightemitting devices 110, respectively. More particularly, one lightemitting device 110 has the four bump electrodes bp, and the four upperelectrodes 11 pa are provided on the printed circuit board 11 p for onelight emitting device 110. The four bump electrodes bp of each lightemitting device 110 are overlappingly disposed to be connected to thefour upper electrodes 11 pa, respectively.

In an exemplary embodiment, the first to third bump electrodes of thefirst light emitting device 110 are connected to the first to third scanlines, respectively, and the fourth bump electrode is connected to thefirst data line. The first to third bump electrodes of the second lightemitting device 110 are connected to the first to third scan lines,respectively, and the fourth bump electrode is connected to the seconddata line. The first to third bump electrodes of the third lightemitting device 110 are connected to the fourth to sixth scan lines,respectively, and the fourth bump electrode is connected to the firstdata line. The first to third bump electrodes of the fourth lightemitting device 110 are connected to the fourth to sixth scan lines,respectively, and the fourth bump electrode is connected to the seconddata line.

Each of eight lower electrodes is disposed on the rear surface of theprinted circuit board 11 p. The eight lower electrodes correspond tofirst to sixth scan pads providing the scan signal to the first to sixthscan lines, and first and second data pads providing the data signal tothe first and second data lines. For example, when the eight lowerelectrodes formed on the rear surface of the printed circuit board 11 pare first to eighth lower electrodes 11 pc_1, 11 pc_2, 11 pc_3, 11 pc_4,11 pc_5, 11 pc_6, 11 pc_7, and 11 pc_8, first to sixth lower electrodes11 pc_1 and 11 pc_2, 11 pc_3, 11 pc_4, 11 pc_5, and 11 pc_6 correspondto the first to sixth scan pads, and the seventh and eighth lowerelectrodes 11 pc_7 and 11 pc_8 correspond to the first and second datapads. However, arrangement and order of the first to sixth scan pads andthe first and second data pads may be not limited thereto, and may bearranged on the rear surface of the printed circuit board 11 p invarious shapes and areas, and the order thereof may be set differently.

In an exemplary embodiment, a distance between two lower electrodesadjacent to each other may be greater than a distance between two upperelectrodes adjacent to each other. In forming the light emitting devicepackage, the lower electrodes of the printed circuit board may functionas connection electrodes for electrical connection with anotherelectronic device when the light emitting device package is mounted onanother electronic device, and thus, a gap between the two lowerelectrodes adjacent to each other is relatively wide. Therefore, thelight emitting device package may be more easily mounted on anotherelectronic device.

As described above, the light emitting device package according to anexemplary embodiment may use the printed circuit board of a simplestructure, and the light emitting device that can be individually drivenmay be easily mounted on the printed circuit board. In addition, onlyeight input terminals (i.e., the eight lower electrodes) may be providedwhen driving four light emitting devices, and thus, the plurality oflight emitting devices may be driven with a simple structure.

According to an exemplary embodiment, the light emitting device packagemay be applied to another device in various forms, such as a singlelight emitting device package used as a light source, or a module usedas a light source, in which a plurality of light emitting devicepackages are mounted on a base substrate to be modularized. Examples ofdevices using the light emitting device package(s) include a displaydevice, a living lighting device, vehicle lighting (vehicle headlights,lighting lamps, taillights, etc.), various decorative lighting devices,and the like.

FIG. 13 is a schematic cross-sectional view illustrating a light sourcemodule manufactured by mounting the plurality of light emitting devicepackages 110D on a base substrate 11 b for application to a displaydevice or a vehicle lighting device according to an exemplaryembodiment.

Referring to FIG. 13 , the base substrate 11 b having wires may beprepared and the plurality of light emitting device packages 110D may bemounted on the base substrate 11 b. The base substrate 11 b may or maynot have flexibility.

The wires on the base substrate 11 b are provided to correspond to thelower electrodes of the light emitting device packages 110D. The wireson the base substrate 11 b may be connected to the lower electrodes ofthe light emitting device package through connection electrodes 11 s. Inan exemplary embodiment, the connection electrodes 11 s may each beprovided as a solder.

In the light emitting device packages mounted on the base substrate asillustrated in FIG. 13 , when a defect occurs in any one of the lightemitting device packages, the defective light emitting device packagemay be replaced with a good product and be easily repaired.

FIG. 14 is a plan view conceptually illustrating a light emitting devicepackage according to an exemplary embodiment applied to a displaydevice, and FIG. 15 is an enlarged plan view of portion P1 of FIG. 14 .

FIGS. 14 and 15 , the light emitting device according to an exemplaryembodiment may be employed as a pixel in a display device capable ofdisplaying various colors. The plurality of light emitting device may bemounted on a base substrate in a form of the light emitting devicepackages 110D described above.

A display device 100 according to an exemplary embodiment may displayarbitrary visual information, for example, text, video, photographs,two-dimensional or three-dimensional images, and the like.

The display device 100 may be provided in various shapes, for example, aclosed polygon including straight sides such as a rectangle, circles andellipses including sides formed of curves, and semicircle andsemi-ellipse including sides of straight lines and curves. In theillustrated exemplary embodiment, the display device is exemplarilyshown as having a rectangular shape.

The display device 100 has a plurality of pixels 110 for displaying animage. Each of the pixels 110 may be implemented as one light emittingdevice as a minimum unit for displaying the image. Each pixel 110 mayinclude a light emitting device having the above-described structure andmay emit white light and/or color light.

In an exemplary embodiment, each pixel 110 includes a first pixel 110_(R) which emits red light, a second pixel 110 _(G) which emits greenlight, and a third pixel 110 _(B) which emits blue light. The first tothird pixels 110 _(R), 110 _(G), and 110 _(B) may correspond to thefirst to third epitaxial stacks of the light emitting device describedabove, respectively.

Light emitted from the first to third pixels 110 _(R), 110 _(G), and 110_(B) is not limited thereto. In addition, at least two pixels 110 mayemit light having the same color or may emit light having differentcolors from each other, for example, may emit light having differentcolors from that described above, such as yellow, magenta, cyan, and thelike.

The pixels 110 are arranged in a matrix shape. As used herein, thearrangement of the pixels 110 in the matrix shape not only refer thatthe pixels 110 are arranged in an exact line along a row or a column,but also that the pixels 110 are generally arranged along rows orcolumns and details are capable of being changed, such as arranged in azigzag pattern.

According to exemplary embodiments, it is possible to easily manufacturelighting devices of various sizes by simply mounting the plurality oflight emitting device packages on the base substrate. For example, alarge area display device may be easily manufactured using the pluralityof light emitting device packages according to exemplary embodiments. Inaddition, when the base substrate or the printed circuit board isflexible, the display device may also be flexible, and thus, varioustypes of display devices, for example, a rollable display device, afoldable display device, and a curved display device, may be easilymanufactured.

According to an exemplary embodiment, the light emitting device packagehaving the simple structure that may be formed by a simple manufacturingmethod, and a display device including the same are provided.

Although certain exemplary embodiments and implementations have beendescribed herein, other embodiments and modifications will be apparentfrom this description. Accordingly, the inventive concepts are notlimited to such embodiments, but rather to the broader scope of theappended claims and various obvious modifications and equivalentarrangements as would be apparent to a person of ordinary skill in theart.

What is claimed is:
 1. A light emitting device comprising: a printed circuit board having a front surface and a rear surface; at least one light emitting source disposed on the front surface and configured to emit light in a direction away from the printed circuit board; and a molding layer disposed on the printed circuit board and surrounding the light emitting source, wherein the light emitting source includes: a light emitting structure disposed on the printed circuit board; a substrate disposed on the light emitting structure; and a plurality of bump electrodes disposed between the light emitting structure and the printed circuit board, wherein the molding layer covers an upper surface of the substrate and a fine concavo-convex part is formed on a surface of the molding layer exposed to the outside. 